Beautiful Spiral Galaxy Has Oddly Flat Center

This stunner of a galaxy, called NGC 3621, may look like a run-of-the-mill spiral galaxy. But closer observation shows that it’s missing the characteristic central bulge that marks most spiral galaxies.

NGC 3621 is a fairly bright galaxy, easily visible to medium-sized telescopes, that lies about 22 million light-years away in the constellation Hydra.

At a glance, it looks like an ordinary classical spiral galaxy. But this new image from the Wide-Field Imager camera on the 2.2 meter telescope at the La Silla observatory in Chile reveals that it’s actually a “pure disc” galaxy, lacking a central bulge that marks an ancient galactic collision.

Astronomers think most galaxies grow by merging with other galaxies, a process that over time should build up large blobs of material at the galaxy’s center. NGC 3621’s surprising flatness indicates that it hasn’t had such a close encounter with another galaxy. Recent research suggests that such pancaked galaxies are actually relatively common.

The data for this image were selected by Joe DePasquale as part of the European Southern Observatory’s Hidden Treasures contest. DePasquale’s image of NGC 3621 was ranked fifth in the competition.